21221000111 has 4 divisors (see below), whose sum is σ = 21223355832. Its totient is φ = 21218644392.

The previous prime is 21221000083. The next prime is 21221000131. The reversal of 21221000111 is 11100012212.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21221000111 is a prime.

It is a super-2 number, since 2×21221000111² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21221000092 and 21221000101.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21221000131) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1164296 + ... + 1182381.

It is an arithmetic number, because the mean of its divisors is an integer number (5305838958).

Almost surely, 2^21221000111 is an apocalyptic number.

21221000111 is a deficient number, since it is larger than the sum of its proper divisors (2355721).

21221000111 is an equidigital number, since it uses as much as digits as its factorization.

21221000111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2355720.

The product of its (nonzero) digits is 8, while the sum is 11.

Adding to 21221000111 its reverse (11100012212), we get a palindrome (32321012323).

The spelling of 21221000111 in words is "twenty-one billion, two hundred twenty-one million, one hundred eleven", and thus it is an aban number.